package/alsa-utils: remove --disable-alsatest

package/alsa-utils: remove --disable-alsatest

atopology is needed to build alsa-utils since version 1.2.1 and
https://github.com/alsa-project/alsa-utils/commit/c8fdd38c74de2e8b7b2b5a4576787d5e9b4ae807

However, atopology is not correctly detected if --disable-alsatest is
passed so drop --disable-alsatest that is not needed since commit
2c03ec15307b567fd2250fe2a7981a89d19b87a9 (from 2002), which removed
AC_TRY_RUN

Fixes:
 - http://autobuild.buildroot.org/results/d0fb760669b02b813115af04adcf24530d35f4e1

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>